Gate Recessed Quasi-Normally OFF Al2O3/AlGaN/GaN MIS-HEMT With Low Threshold Voltage Hysteresis Using PEALD AlN Interfacial Passivation Layer

In this letter, a gate recessed normally OFF AlGaN/GaN MIS-HEMT with low threshold voltage hysteresis using Al
₂
O
₃
/AlN stack gate insulator is presented. The trapping effect of Al
₂
O
₃
/GaN interface was effectively reduced with the insertion of 2-nm AlN thin interfacial passivation layer grown by plasma enhanced atomic layer deposition. The device exhibits a threshold voltage of +1.5 V, with current density of 420 mA/mm, an OFF-state breakdown voltage of 600 V, and high ON/OFF drain current ratio of ~10
⁹
.